Human neuroimaging of acute and chronic marijuana use: Implications for frontocerebellar dysfunction

Citation
Rt. Loeber et Da. Yurgelun-todd, Human neuroimaging of acute and chronic marijuana use: Implications for frontocerebellar dysfunction, HUM PSYCHOP, 14(5), 1999, pp. 291-304
Citations number
72
Categorie Soggetti
Neurosciences & Behavoir
Journal title
HUMAN PSYCHOPHARMACOLOGY-CLINICAL AND EXPERIMENTAL
ISSN journal
08856222 → ACNP
Volume
14
Issue
5
Year of publication
1999
Pages
291 - 304
Database
ISI
SICI code
0885-6222(199907)14:5<291:HNOAAC>2.0.ZU;2-A
Abstract
The effects of cannabis use on the human brain are not well understood. Rec ently neuroimaging research has begun to address the question of metabolic changes secondary to (1) long-term chronic cannabis use, and (2) acute into xication due to cannabis smoke or injection of delta-9-tetrahydrocannabinol (Delta(9)-THC) solution. A comprehensive review of the neuroimaging litera ture was performed. To further interpret and understand this research, lite rature addressing animal receptor and neurochemical models were also survey ed. Neuroimaging findings have concluded that abstinence from smoking resul ts in depressed cerebral metabolism in chronic users, while acute exposure reverses this condition, producing higher cerebral blood flow in chronic us ers compared to controls. These changes are hypothesized to be associated w ith alterations of cannabinoid receptors secondary to chronic exposure. Fin dings from animal models are consistent with the proposition that adaptatio n to chronic exposure results in adjustment of normal neurotransmitter leve ls. The frontopontocerebellar network is implicated as a site sensitive to cannabinoid-induced alterations in the levels of dopaminergic activity deri ved through the medial forebrain bundle, which projects from the ventral te gmental area. This network is involved in the modulation of a range of huma n behavior that is clearly altered by use of cannabis. The combined neuroim aging and animal data suggest that metabolism of component regions of the f rontopontocerebellar network are altered by acute and chronic exposure to c annabis through modulation of both the cannabinoid and the dopamine system. Copyright (C) 1999 John Wiley & Sons, Ltd.